﻿#define _CRT_SECURE_NO_WARNINGS 1
#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
#include <string.h>
#include <math.h>
#include <unordered_map>
using namespace std;

 struct TreeNode {
      int val;
      TreeNode *left;
      TreeNode *right;
      TreeNode() : val(0), left(nullptr), right(nullptr) {}
      TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
      TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
  };

class Solution {
public:
    vector<int> rightSideView(TreeNode* root) {
        if (!root) return {};
        queue<TreeNode*> qt;
        qt.push(root);
        vector<int> ret;
        while (qt.size())
        {
            int num = qt.size();
            while (num--)
            {
                TreeNode* tmp = qt.front();
                qt.pop();
                if (num == 0) ret.push_back(tmp->val);
                if (tmp->left) qt.push(tmp->left);
                if (tmp->right) qt.push(tmp->right);
            }
        }
        return ret;
    }
};

int main()
{
    return 0;
}